Samsung SM951 (512GB) PCIe SSD Review
by Kristian Vättö on February 24, 2015 8:00 AM ESTAnandTech Storage Bench - The Destroyer
The Destroyer has been an essential part of our SSD test suite for nearly two years now. It was crafted to provide a benchmark for very IO intensive workloads, which is where you most often notice the difference between drives. It's not necessarily the most relevant test to an average user, but for anyone with a heavier IO workload The Destroyer should do a good job at characterizing performance.
| AnandTech Storage Bench - The Destroyer | ||||||||||||
| Workload | Description | Applications Used | ||||||||||
| Photo Sync/Editing | Import images, edit, export | Adobe Photoshop CS6, Adobe Lightroom 4, Dropbox | ||||||||||
| Gaming | Download/install games, play games | Steam, Deus Ex, Skyrim, Starcraft 2, BioShock Infinite | ||||||||||
| Virtualization | Run/manage VM, use general apps inside VM | VirtualBox | ||||||||||
| General Productivity | Browse the web, manage local email, copy files, encrypt/decrypt files, backup system, download content, virus/malware scan | Chrome, IE10, Outlook, Windows 8, AxCrypt, uTorrent, AdAware | ||||||||||
| Video Playback | Copy and watch movies | Windows 8 | ||||||||||
| Application Development | Compile projects, check out code, download code samples | Visual Studio 2012 | ||||||||||
The table above describes the workloads of The Destroyer in a bit more detail. Most of the workloads are run independently in the trace, but obviously there are various operations (such as backups) in the background.
| AnandTech Storage Bench - The Destroyer - Specs | ||||||||||||
| Reads | 38.83 million | |||||||||||
| Writes | 10.98 million | |||||||||||
| Total IO Operations | 49.8 million | |||||||||||
| Total GB Read | 1583.02 GB | |||||||||||
| Total GB Written | 875.62 GB | |||||||||||
| Average Queue Depth | ~5.5 | |||||||||||
| Focus | Worst case multitasking, IO consistency | |||||||||||
The name Destroyer comes from the sheer fact that the trace contains nearly 50 million IO operations. That's enough IO operations to effectively put the drive into steady-state and give an idea of the performance in worst case multitasking scenarios. About 67% of the IOs are sequential in nature with the rest ranging from pseudo-random to fully random.
| AnandTech Storage Bench - The Destroyer - IO Breakdown | |||||||||||
| IO Size | <4KB | 4KB | 8KB | 16KB | 32KB | 64KB | 128KB | ||||
| % of Total | 6.0% | 26.2% | 3.1% | 2.4% | 1.7% | 38.4% | 18.0% | ||||
I've included a breakdown of the IOs in the table above, which accounts for 95.8% of total IOs in the trace. The leftover IO sizes are relatively rare in between sizes that don't have a significant (>1%) share on their own. Over a half of the transfers are large IOs with one fourth being 4KB in size.
| AnandTech Storage Bench - The Destroyer - QD Breakdown | ||||||||||||
| Queue Depth | 1 | 2 | 3 | 4-5 | 6-10 | 11-20 | 21-32 | >32 | ||||
| % of Total | 50.0% | 21.9% | 4.1% | 5.7% | 8.8% | 6.0% | 2.1% | 1.4 | ||||
Despite the average queue depth of 5.5, a half of the IOs happen at queue depth of one and scenarios where the queue depths is higher than 10 are rather infrequent.
The two key metrics I'm reporting haven't changed and I'll continue to report both data rate and latency because the two have slightly different focuses. Data rate measures the speed of the data transfer, so it emphasizes large IOs that simply account for a much larger share when looking at the total amount of data. Latency, on the other hand, ignores the IO size, so all IOs are given the same weight in the calculation. Both metrics are useful, although in terms of system responsiveness I think the latency is more critical. As a result, I'm also reporting two new stats that provide us a very good insight to high latency IOs by reporting the share of >10ms and >100ms IOs as a percentage of the total.
The SM951 takes the lead easily and provides ~34% increase in data rate over the XP941. The advantage over some of the slower SATA 6Gbps drives is nearly threefold, which speaks for the performance benefit that PCIe and especially PCIe 3.0 provide.
The latency benefit isn't as significant, which suggests that the SM951 provides substantial boost in large IO performance, but the performance at small IO sizes isn't dramatically better.
Despite the lowest average latency, the SM951 actually has the most >10ms IO with nearly 2% of the IOs having higher latency than 10ms. I did some thermal throttling testing (see the dedicated page for full results) and the SM951 seems to throttle fairly aggressively, so my hypothesis is that the high number is due to throttling, which limits the drive's throughput momentarily (and hence increases the latency) to cool down the drive.
However, the SM951 has the least >100ms IOs, which means that despite the possible throttling the maximum service times stay between 10ms and 100ms.
Facebook
Twitter
RSS
128 Comments
View All Comments
peevee - Friday, March 20, 2015 - link
IOmeter? Packing several weeks/months of IO into a several minutes/hours test? Seriously, your tests have become SO artificial as not to correspond to any real life experiences at all. For example, in real life SSD write speed almost does not matter, because almost always they are asynchronous - write happens into cache and user does not wait anything, or speed of writes is limited by the speed of data acquisition - case in point, you download test is always limited by much slower internet speed, or copying pictures off camera/SD card are limited by much slower camera/reader, USB or SD speeds etc. Background backup, happening without a user AT ALL? Come on!It would be actually much more interesting to see at least a few REAL numbers, like good old starting Windows or copying a catalog full of pictures and videos or starting a VM. So the users would see what amount of their time they would REALLY save by investing extra into a faster drive.
kishisaki - Tuesday, April 7, 2015 - link
How did you get all those speed with Asus Z97 Deluxe?I thought it only has a 10Gb/s M.2 Slot?
Gradius2 - Wednesday, April 15, 2015 - link
My solution is WAYYYY cheaper and bigger, I have 670GB (real size) on my little RAID, see the performance: http://i61.tinypic.com/2vt9mo6.jpgxyvyx2 - Wednesday, July 22, 2015 - link
I was able to keep the temps down on my SM951 by attaching a small heatsink... I need to do some data logging, but I don't think it's gone over 60C since:http://s76.photobucket.com/user/xyvyx/media/Comput...">[IMG]http://i76.photobucket.com/albums/j9/xyvyx/Compute...[/IMG]
stevae - Wednesday, August 12, 2015 - link
why isn't there a trouble shoot included IF your result comes back that the drive DOES NOT have trim working? this is incomplete article.Invisibleman - Sunday, August 16, 2015 - link
Kristian,Because I didn't read this review earlier and I am now planning to upgrade my PC to an M2 SSD. I came to this review.
But there is one thing I realy don't understand. As the setup is saying, you have tested with de Asus Z97 DeLuxe. I know there are 2 different versions of this one. 1 is with USB 3.1 support (new version) and 1 with USB 3.0 (Old one) this one I have.
But if I look at the specs then the Z97 DeLuxe shares the bandwide with SataExpress 1 and have only 2 x PCI Express 3.0/2.0 x 16 Slots (Single at 16x or dual at x8/x8 Mode)
But as I read the SM951 needs to have PCI 3.0 x 4bus. Am I missing something? For me it seems that the SM951 can't run full speed on this board. If it goes thru Sata Express then also get only PCI 3.0 X 2. But in the test (charts) you are mention PCI 3.0 x 4. How is this possible to get if the Max is PCI 3.0 x 2?
So can you tell me what I am missing? What do I need to do/buy extra to get this one run one full power meaning PCI 3.0 x 4.
Regards,
Hans
Hoogmade - Monday, December 7, 2015 - link
What card is used to use the SM951 in a Mac Pro 2012?I tried the Addonics ADM2PX4 but that doesn't seem to work.
dtscaps - Friday, March 11, 2016 - link
Ok, this is supposed to be a review to guide me what SSD to buy. I read 10 pages of performance specs and 72 more comments dealing with microseconds marginality. The fact that this drive does or does not have an AES self encrypting mechanism adering to OPAL 2 with a possible IEEE1667 extension IS IMPORTANT. IT IS A COMPLETE SHOW STOPPER if the drive cannot encrypt data. Maybe except if you are a kid playing with new toys.So, is this SSD self encrypting ?
Does it support Opal 2
Does it support the IEEE1667 extension?